Process and apparatus for dosing electrical devices



Sept. 28, 1965 PROCESS AND APPARATUS FOR DOSING ELECTRICAL DEVICES W. L.BRUNDIGE ETAL Filed Jan. 25, 1965 CARRIER GAS @EMICAL DRYER 47 Z u*FLUSH GAS FILL GAS FRE/V675 H. BEH/VE.

WILL/HM L. BRUNO/65.2:

United States Patent O 3,208,812 PROCESS AND APPARATUS FOR DOSINGELECTRICAL DEVICES William L. Brundige, West Caldwell, and Francis A.

Beane, Bloomfield, NJ., assignors to Westinghouse Electric Corporation,Pittsburgh, Pa., a corporation of Pennsylvania Filed Jan. 25, 1963, Ser.No. 253,807 10 Claims. (Cl. 316-21) This invention relates to electricaldevices and has particular reference to an improved process andapparatus for dosing radiation-generating devices with volatilehighly-reactive materials such as iodine or the like.

While the present invention can be used with advantage in making varioustypes of electrical devices, it is especially adapted for use in themanufacture of so-called T3 quartz lamps recently developed and nowbeing marketed. These lamps generate both visible and infraredradiations and can thus be used for lighting or heating purposes. Thepresent invention is directed primarily to lamps that are intended foruse as light rather than heat sources and are thus more aitected by bulbblackening.

Such lamps vare generally of tubular or pencil-like configuration andcontain `a coiled filament that extends along the axis of the envelopeand is held in this position by a series of tungsten-wire supports. Inaddition to the usual inert gas till these lamps are dosed with aprecisely measured quantity of iodine which vaporizes when the lamp isoperated. An iodine-tungsten cycle occurs within the lamp during usewhich keeps the bulb Walls substantially free from vaporized tungsten.Such lamps accordingly remain clean and have very good maintenancethroughout their life and are very efficient. Radiation-generatingdevices of this type are disclosed in U.S. Patent 2,883,571, entitledElectric Incandescent Lamp, issued April 21, 1958 to E. G. Fridrich etal.

Since iodine is so active chemically the introduction of very carefullymeasured quantities into the envelopes of such lamps presents a verydifficult problem. Var-ious schemes for dosing the lamp by mechanicallytransferring measured quantities of iodine granules or crystals into theenvelope were tried but abandoned because they were too costly, too slowand damaged to stop cocks etc. used to protect the lamp from theatmosphere during the dosing operation.

As a result, the iodine content varied considerably from lamp to lamp,and, since the performance of the lamp is directly related to the amountof iodine sealed in the envelope, lamp quality could not be adequatelycontrolled. This problem is aggravated by the fact that the iodinedosing must be accomplished during the exhaust and gaslling operationsbefore the envelope is tipped off and must, therefore, be achievedWithout introducing any solid or gaseous impurities into the envelope oropening it up to the atmosphere.

It is accordingly the general object of this invention to provide aneliicient means for introducing a predetermined quant-ity of a volatilematerial into the envelope of an electrical device without interferingwith the other operations required to manufacture it.

Another object is the provision of a process for dosing aradiation-generating device with `a precisely controlled amount of avolatile material quickly and conveniently during the normal sequence ofoperations required to complete the manufacture of the device.

A further object is the provision of a process for dosing the envelopeof a lamp or the like with predetermined amounts of iodine and a lillgas while it is protected from the atmosphere.

Still another object of the invention is the provision of a simple andinexpensime apparatus for carrying out the above-mentioned processes.

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The foregoing objects, and other advantages which will become apparentto those skilled in the art, are achieved in accordance with the presentinvention by introducing the volatile material into the envelope in theform of a vapor and directing it into heat-exchanging relationship witha region inside the lamp that has been cooled below the condensationtemperature of the vapor. The vapor thus condenses at this region and,after the desired amount of the material has been deposited and theexhaust or gasiilling operations have been completed, the envelope issealed.

In the case of the aforementioned T3 quartz lamps, the iodine vapor isentrained in a suitable inert carrier gas, such as nitrogen, and acontrolled amount of the vapor-laden gas is dispensed intoheat-exchanging relation with a cooled portion of the envelope. The fillgas (argon, for example) can also be used as the carrier 4gas in whichcase the envelope will be dosed and lled at the same time. Apparatus for-cooling the envelope to the proper temperature and injecting thevapor-laden carrier gas into the envelope through an attached tubulationby means of a hollow probe in accordance with one embodiment of theinvention is also provided.

A better understanding of the invention will be obtained by referring tothe sole figure in the accompanying drawing which illustrates one formof apparatus for introducing predetermined amounts of iodine and argonfill gas into the envelope of a tubular lamp.

The apparatus With specific reference to the drawing, the apparatusthere shown is designed to dose a tubular T3 lamp 10 with a measuredamount of iodine, and then fill it with la predetermined amount of argonwhile it is protected from the atmosphere. As illustrated, the lamp 10comprises 'a pencil-like envelope 12 of quartz or t-he like thatcontains an axially-extending coiled tungsten filament 14. The filamentis held in this position by a series of spaced tungsten-wire supports 16and by press seals 18 at each end of the envelope in which the customarylead-in conductor Iassemblies 20 are embedded. The lamp 10 at this stageof fabrication is provided with an arm or exhaust tubulation 22 ofquartz or the like that extends from the side of the envelope 12.

According to the illustrated apparatus embodiment the tubulated lamp 10is held during the iodine-dosing and gas-tilling operations in thedesired position by a head 24 that is fastened to a stationary support25. The head 24 is .provided with an axially extending aperture 26 and alaterally extending port 27 that communicates with the aforesaidaperture. A suitable apertured sealing means such as acompression-rubber assembly 28 is mounted on the upper face of the head24 and a second compressionrubber assembly 30 is mounted on the lowerface of the head. The openings in the aforesaid compression-rubberassemblies are aligned with the aperture 26 in the head 24 so that, whenthe compression-rubber assemblies are open, a vertical passageway isprovided that extends completely through the head. Suchcompression-rubber assemblies are well known in the art and are soconstructed that they effect an airtight seal with an insertedtubulation or plug when the assemblies ar-e actuated by moving thelevers 29 and 31, respectively.

The evacuation, iiushin-g and filling of the lamp 10 loaded into thehead 24 is accomplished by connecting the :laterally extending port 27with a suitable conduit 32 which, lin turn, is joined to three branchconduits 34, 36 and 38 that connect witha supply of iiush gas such asnitrogen, a suitable vacuum system (not shown) and a -supply of iill gassuch as argon, respectively. These ush, vacuum and iill gas lines areprovided with suitable valves 35, 37 and 39, respectively, so that thelamp 10 may be sequentially ushed and evacuated and then iilled byoperating the proper valves.

1t may be desirable, or even preferable in some cases, to ush the lampwith the same type of gas used as the fill gas. This would furtherreduce the manufacturing cost of the lamp since it eliminates the needfor a separate flush -gas line and system and simplifies the entireoperation.

It should be borne in mind that since no chemical getters are used inthe lamp, it is extremely important that only dry pure gas be used asthe carrier, flush and fill gases to avoid contaminating and ruining thelamp.

The loaded lamp is dosed With a predetermined amount of iodine inaccordance with the present invention by means of a dosing system thatis coupled to the lamp at the proper time. In the embodiment shown inthe drawing, the major component of this system is a doser unit 40 whichcomprises an elongated enclosure, such as a glass tube 42, and anattached hollow needlelike pr-obe 60 that is insertable into the head24. The doser tube 42 has an -opening 43 near its closed end and asecond opening 44 at its opposite end. The tube is packed with thefollowing materials which are separated from each other and arranged inthe order in which they are named, starting from the closed end of thetube and proceeding toward its mouth; a filling of suitable filtermaterial 45 such as glass wool or the like, a lling or reservoir ofloosely packed iodine crystals or granules 46, a filling of looselypacked beads of a suitable chemical dryer 47 that does not react witheither iodine or the carrier gas that is used, and a second lling ofglass wool or other suitable filter material 48. A removable plug 49 isinserted into and closes the mouth of the doser tube. As shown, thecompartment containing the filling 45 of filter material communicateswith the opening 43 and the other chamber lled with filter material 48communicates with the other opening 44 in the tube 42.

The opening 43 is connected by means of a conduit 50, a valve 52 and atubing 54 to a supply of a suitable carrier gas, such as nitrogen orargon, that does not react with iodine. The operation of the valve 52 inthe illustrated embodiment is controlled by an electrical timer 56 sothat the carrier gascan be fed through the dosing unit 40 for apredetermined length of time and at a preselected pressure andtemperature.

The other opening 44 in the doser tube 42 is provided with a nipple 57that is hermetically joined by means of a collar 58 to theaforementioned probe 60. The probe has a diameter that is considerablysmaller than both the bore of the lamp tubulation 22 and the aperture 26in the head 24, and it is of suicient length to extend through the headand the tubulation into the partly fabricated lamp 10 loaded into thehead. There is, accordingly, a gap or space 61 between the insertedprobe 60 and the wall of the tubulation 22 through which iiush gas, andcarrier gas that has been purged of iodine vapor, can be vented to theatmosphere through the head 24 and the upper compression-rubber assembly28 when the latter is opened, as shown in the drawing.

According to the form lof the invention illustrated in the drawing,cooling of the envelope 12 to a predetermined temperature below that ofthe iodine vapor entrained in the carrier gas is accomplished byimmersing the lamp 10 in a container 64 lled with a suitable liquidcoolant such as ice water 65. The container is mounted on a suitablesupport 68 that is located below and is movable toward and away from thehead 24, as indicated by the arrow in the drawing, so that a lamp loadedin the head can be immersed in and subsequently withdrawn from thecontainer of ice water.

In order to avoid localized supercooling of the envelope -12 andresultant variations in the amount of iodine vapor condensed into thelamp 10, a baffle (not shown) is desirably mounted within the container64 to prevent the pieces of ice 66 from contacting the envelope. S-altmay be also added to the ice water and the water stirred to 4 maintainit at a uniform temperature of about 0 C. ill" C.

The doser tube 42, nipple 57 and collar 58 are desirably fabricated fromglass or quartz or some other vitreous material that does not react withiodine. To avoid breakage the probe 60 is preferably fabricated from ametal such as No. 316 stainless steel or the like that is not readilycorroded by iodine. Tantalum and platinum, although costly, would bepreferable since they are even less subject to attack. The metalportions of the head 24 and all other parts of the system which are madeof metal and might come in contact with iodine vapor are also made froma similar material.

It is desirable to pass the iodine-vapor-laden carrier gas through achemical dryer 47 to remove moisture from the Vapor which, if introducedinto the lamp, would cause short life. Phosphorus pentoxide has givensatisfactory results and, surprisingly, does not even discolor theiodine vapor. Other suitable drying agents are calcium chloride(anhydrous) and calcium nitrate, and mixtures thereof. An adsorbentmaterial such as sodium zeolite or potassium zeolite that gettersmoisture by a molecular sieve type action can also be used. Thesematerials are well known and are disclosed in U.S. Patent Nos. 2,882,243and 2,882,244. Such materials aiord the additional advantage ofgettering trace amounts of oxygen that may be present in the carrier gasand would otherwise be introduced into the lamp during the dosingoperation.

The process In general, dosing of the partly-fabricated lamp 10 isaccomplished in accordance with the illustrated embodiment of thepresent invention by rst entraining predetermined amounts of iodinevapor in the carrier gas by passing the latter through the dosing unit40 at a controlled rate of flow while the doser is maintained atapproximately room temperature (20 C.). If nitrogen is the carrier gas,the iodine-vapor-laden nitrogen is then injected into the cooled lamp 10through the probe 60 in such a manner that the gas impinges upon and isthus placed in heat-exchanging relationship with the part of theenvelope wall located substantially opposite the mouth of the tubulation22. A predetermined percentage of the entrained iodine vapor condensesonto the chilled envelope wall and a layer or lm 62 of iodine forms atthis point on the envelope surface, as illustrated in the drawing. Sincethe vapor pressure of iodine at 20 C. is about 0.20 mm. and drops toabout 0.01 mm. at 10 C., the percentage of the entrained iodine vaporwhich condenses inside the cooled envelope is controlled by thetemperature differential that exists between the vapor and the cooledportion of the envelope.

The nitrogen from which iodine vapor has been removed is vented to theatmosphere through the space 61 between the probe 60 and the tubulation22 and then through the head 24 and the open compression-rubber assembly28. This gas ow, in conjunction with the ush gas that is continually fedinto the lamp during the dosing operation, maintains a positive pressurein the aforesaid opening and forms a dynamic seal or barrier thatprotects the loaded lamp 10 from the atmosphere. The vapor-ladennitrogen is fed into the lamp 10 at a preselected pressure and for apreselected time (set on the timer 56) so that a precisely-controlledamount of iodine 62 is introduced into the lamp.

The probe is then withdrawn, the compression assembly 28 is closed, theenvelope 12 (while still in its cooled condition) evacuated and lledwith argon, and the tubulation 22 sealed at a point adjacent theenvelope thus completing the fabrication of the lamp.

If argon is used as the carrier gas instead of nitrogen, then dosingandflling of the lamp 10 will, of course, be accomplishedsimultaneously. In this case, the probe 60 is only partly withdrawn fromthe tubulation 22 after the dosing and filling operations are completedand the tubulation is tipped off at a point adjacent the envelope whilethe vapor-laden argon is still flowing through the probe and out of theopen end of the tubulation. Since the lamp is already illed with argonthe iodine-vaporladen argon will flow out through the space 61 ratherthan into the envelope and no more iodine will condense inside the lamp.The amount of iodine deposited in the lamp is thus accurately controlledby the dosing operation in the same manner as when it is carried outindependently of the filling operation.

Specific example Following is a specic example of a schedule ofoperations for sequentially iodine-dosing and gas-filling a T3 quartzlamp or the like according to the teachings of the present inventionusing nitrogen as the carrier gas and the apparatus illustrated in thedrawing:

(1) Insert the tubulated lamp 10 into the head 24, close the lowercompression assembly 30 and seal oif the upper assembly 28 by means of aglass plug (not shown).

(2) Alternately exhaust the lamp down to 10 microns or less and thenflush with an inert gas such as nitrogen at a pressure of 100millimeters above atmospheric pressure by manipulating valves 35 and 37,and continue for three cycles.

(3) Heat the lamp to a temperature lof at least 750 C. for five minutesby placing it in an oven and alternately flush and exhaust for threecycles (during the first two cycles exhaust to a pressure of about 10microns and during the last cycle to about five microns or less).

(4) Cool the envelope to a temperature of about 0 C ilu C. by immersingit in the container 64 of ice water.

(5 Open valve 35 and ush nitrogen at the aforesaid pressure through thecooled envelope until after the dosing operation (step 6 below) iscompleted.

(6) Open the upper compression-rubber assembly 28 and insert doserneedle or probe 60 through the head 24 and tubulation 22 and into theenvelope 12 until the tip of the probe is proximate the envelope wall.Flush the nitrogen carrier gas through the doser 40 for a predeterminedlength of time at about 100 millimeters above atmospheric pressure untilthe desired amount of iodine condenses on the cooled envelope wall. Inthe specific case of a 500 watt tubular heat lamp approximately 3.15inches long and having an O.D. of 3A; inch, the vaporladen nitrogen isinjected into the envelope for approximately seconds when nitrogen atapproximately room temperature is fed through the doser at theaforementioned pressure and 12 cc. of iodine crystals are present in thedoser, which is also maintained at room temperature.

(7) After the iodine dosing operation has been completed, withdraw thedosing probe 60 from the head 24 and re-insert the plug and seal off theupper compressionrubber assembly 28 from the atmosphere.

y(8) Exhaust the lamp 10 to about 2() microns and flush once withnitrogen to a till pressure of about 50 to 100 millimeters.

(9) Exhaust the lamp to about 2O microns and flush once with argon to all pressure of about to 50 millimeters.

(10) Finally, exhaust the lamp to 10 microns, or less, and then ll withargon to about 680 millimeters pressure by operating valves 37 and 39.

(11) Remove the lamp from the ice water and tip off the tubulation 22 ata point about 5 millimeters, and preferably less, from the envelope.

If salted ice water has been used, the lamp is then washed in water anddried.

Summary It will be appreciated from the foregoing that a process andapparatus for introducing a predetermined amount of volatile materialand an inert gas into the envelope of an electric lamp or the like hasbeen provided which not only facilitates the manufacture of the lamp,but avoids intolerable variations in the dosage from lamp to lamp andthus improves the lamp quality.

Moreover, the dosing process and apparatus are such that this operationcan ybe carried out during the regular sequence of operations requiredto complete the lamp thus further reducing its manufacturing cost.

While one embodiment has been illustrated and described, it will beappreciated that various structural and procedural modifications can bemade without departing from the spirit and scope of the invention.

-For example, a cold trap may be inserted into the vacuum line toprotect the associated Valves and the exhaust system from iodine vaporand corrosion, and a jet of a gaseous coolant or a refrigerator unit canbe used to chill the part of the envelope located opposite thetubulation instead of immersing the entire envelope in a liquid coolantas shown and described.

We claim as our invention:

l. In the manufacture of a radiation-generating device having anenvelope with a tubulation, the process of dosing the envelope with avolatile material and lling it with an inert gas, which processcomprises,

cooling the portion of said envelope located substantially opposite themouth of said tubulation to a predetermined temperature at which vaporfrom said volatile material will condense,

placing a quantity of said volatile material in a stream of an inertcarrier gas, regulating the temperature of said volatile material andthe rate of flow of the carrier gas to cause the volatile Imaterial tovaporize and the resulting vapor to be entrained in the stream ofcarrier gas at a controlled rate, injecting the vapor-laden stream ofcarrier gas into the envelope through the tubulation and into impingingrelationship with the cooled portion of the envelope so that theentrained vapor condenses thereon,

venting the carrier gas that has impinged upon the cooled portion of theenvelope to the atmosphere,

maintaining the flow of vapor-laden carrier gas into said envelope for apredetermined period of time so that a preselected amount of saidvolatile material condensed on the cooled portion of said envelope,

evacuating said envelope and lling it with a predetermined amount ofinert gas through said tubulation while the aforesaid portion of saidenvelope is still in its cooled condition and the volatile material iscondensed thereon, and then sealing-olf the tubulation at a pointadjacent said envelope.

2. The dosing and gas-filling process as set forth in claim 1 whereinthe stream of vapor-laden carrier gas is treated to remove moisturetherefrom prior to being dispensed into the envelope.

3. The dosing and gas-filling process as set forth in claim 2 wherein;said volatile material comprises iodine, and the stream of vapor-ladencarrier gas is purged of moisture prior to being dispensed into theenvelope by exposing it to a drying agent selected from the groupconsisting of calcium chloride, calcium nitrate, phosphorous pentoxide,sodium zeolite, and potassium zeolite,

4. In the manufacture of a radiation-generating device having anenvelope with a vitreous tubulation, the process of dosing the envelopewith iodine and filling it with an inert gas, which process comprises,

im-mersing the envelope in a liquid coolant to cool it to apredetermined temperature at which iodine vapor will condense,

passing nitrogen through an enclosure that contains iodine and ismaintained at a predetermined temperature above that of the cooledenvelope,

controlling the rate of flow of nitrogen through said enclosure so thata predetermined amount of iodine vapor is entrained in the flowingnitrogen,

injecting the vaporladen nitrogen into the envelope through saidtubulation and impinging it off the inner surface of said cooledenvelope for a predetermined period of time so that the iodine vaporcondenses thereon,

removing the nitrogen from said envelope through a portion of saidtubulation that is isolated from the portion carrying the vapor-ladennitrogen,

maintaining the flow of vapor-laden nitrogen into said envelope for apredetermined period of time so that a preselected amount of iodinecondenses therein,

evacuating and filling said envelope with a predetermined amount ofinert gas through said tubulation while the envelope is still immersedin the coolant and the iodine is in a condensed state, and then tippingoff said tubulation to seal the condensed iodine and lill gas in saidenvelope.

5. The iodine dosing and gas filling process as set forth in claim 4wherein,

said envelope is cooled to a temperature approximately 20 C. below thatof the iodine vapor, and

the iodine-vapor-laden nitrogen is exposed to phosphorous pentoxide toremove moisture therefrom before being injected into said envelope.

6. The iodine-dosing and gas-filling process as set forth in claim 4wherein,

said envelope is immersed in ice water and is thus cooled to atemperature of approximately C., the vaporladen nitrogen is exposed to adrying agent before being injected into said envelope to remove moisturetherefrom, and

the dried vapor-laden nitrogen is also filtered prior to -being injectedinto the cooled envelope to remove solid impurities therefrom.

7. Apparatus for dosing a radiation-generating device or the like with apredetermined amount of a vaporizable material, said device having anenvelope with a tubulation, which apparatus comprises,

a head having an aperture therethrough,

a first sealing means carried by vsaid head and adapted to receive andeffect an air-tight seal with the tubulation attached to said envelope,

a second sealing means carried by said head and located opposite saidfirst sealing means and in alignment therewith and with the aperture insaid head,

means for cooling the portion of said envelope located opposite saidtubulation,

an enclosure for a reservoir of the vaporizable material,

an elongated hollow probe hermetically attached to said enclosure andcommunicating with an opening there- 1n, said probe being insertableinto said second sealing means and dimensioned to fit loosely in andextend through the aperture in said head and the tubulation attached toan envelope loaded in said head, conduit means connected to anotheropening in said enclosure for passing an inert gas through saidenclosure and probe, and means for controlling the iiow of inert gasthrough said enclosure and probe. 8. Dosing apparatus as set forth inclaim 7 wherein, said means for controlling the gas flow comprises atimer-controlled valve in said conduit means, and said enclosurecontains filter means located on the upstream side of the opening thatcommunicates with said probe. 9. Apparatus for dosing aradiation-generating device such as a tubular lamp or the like `with apredetermined amount of a vaporizable material, said device having anenvelope with an attached tubulation, which apparatus comprises,

a head'having an aperture that extends through said head along avertical axis and communicates with a laterally extending port,

a first compression-rubber assembly on the lower face of said headadapted to receive and effect an air-tight seal with the tubulation of alamp loaded in said head,

a second compression-rubber assembly on the upper face of said head andaligned with said first compression-rubberr assembly and the aperturethrough said head,

a container for a liquid coolant adapted to receive said lamp,

means for effecting relative movement between said head and containerand immersing a lamp loaded in said head in said coolant,

an elongated enclosure for containing a reservoir of the vaporizablematerial and a segregated quantity of a chemical drying agent,

said enclosure having an opening at each end,

an elongated hollow probe hermetically coupled to said enclosure andcommunicating with one of said openings,

said probe being insertable into said second compression-rubber assemblyand being of such cross-sectional dimension and length that it looselyfits in and extends through the aperture in said head and the tubulationof a lamp loaded in said head,

conduit means for connecting the other opening in said enclosure to asupply of inert carrier gas,

a timer-controlled valve in said conduit means for regulating the flowof inert carrier gas through said enclosure and probe, and

conduit means for connecting the port in said head to an evacuatingsystem and to a supply of inert flushing and a ll gas.

10Q In the manufacture of an electric lamp or similar device having anenvelope, the process of dosing the envelope with a volatilechemically-active material and filling it .with an inert gas, whichprocess comprises,

cooling a portion of said envelope to a predetermined temperature atwhich vapor from said material will condense,

passing an inert carrier gas through an enclosure containing saidvolatile material,

controlling the temperature of said volatile material and the rate ofowk of said carrier gas through said enclosure so that said materialvaporizes at a predetermined rate and a controlled amount of vapor isentrained in said carrier gas,

introducing the vapor-laden carrier gas into the envelope and directingit into heat-exchanging relationship with the cooled portion of theenvelope to cause entrained vapor to condense thereon,

maintaining the ow of vapor-laden carrier gas into said envelope for apredetermined period of time so that a preselected amount of thevolatile material condenses onthe cooled envelope portion,

evacuating said envelope and filling it with a predetermined amountof'inert gas while the aforesaid portion of the envelope is still in itscooled condition and the volatile material is condensed thereon, andthen sealing the envelope to retain the gaseous filling and condensedvolatile material therein.

References Cited by the Examiner UNITED STATES PATENTS 1,789,556 l/31Machlett 316-20 X 3,093,430 6/ 63 Wiley 316-24 FRANK E. BAILEY, PrimaryExaminer.

1. IN THE MANUFACTURE OF A RADIATION-GENERATING DEVICE HAVING ANELVELOPE WITH A TUBULATION, THE PROCESS OF DOSING THE ENVELOPE WITH AVOLATILE MATERIAL AND FILING IT WITH AN INERT GAS, WHICH PROCESSCOMPRISES, COOLING THE PORTION OF SAID ENVELOPE LOCATED SUBSTANTIALLYOPPOSITE THE MOUTH OF SAID TUBULATION TO A PREDETERMINED TEMPREATURE ATWHICH VAPOR FROM SAID VOLATILE MATERIAL WILL CONDENSE, PLACING AQUANTITY OF SAID VOLATILE MATERIAL IN A STREAM OF AN INERT CARRIER GAS,REGULATING THE TEMPREATURE OF SAID VOLATILE MATERIAL AND THE RATE OFFLOW OF THE CARRIER GAS TO CAUSE THE VOLATILE MATERIAL TO VAPORIZE ANDTHE RESULTING VAPOR TO BE ENTRAINED IN THE STREAM OF CARRIER GAS AT ACONTROLLED RATE, INJECTING THE VAPOR-LADEN STREAM OF CARRIER AS INTO THEENVELOPE THROUGH THE TUBULATION AND INTO IMPINGING RELATIONSHIP WITH THECOOL PORTION OF THE ENVELOPE SO THAT THE ENTRAINED VAPOR CONDENSESTHEREON, VENTING THE CARRIER GAS THAT HAS IMPINGED UPON THE COOLEDPORTION OF THE ENVELOPE TO THE ATMOSPHERE, MAINTAINING THE FLOW OFVAPOR-LADEN CARRIER GAS INTO SAID ENVELOPE FOR A PREDETERMINED PERIOD OFTIME SO THAT A PRESELECTED AMOUNT OF SAID VOLATILE MATERIAL CONDENSED ONTHE COOLED PORTION OF SAID ENVELOPE, EVACUATING SAID ENVELOPE ANDFILLING IT WITH A PREDETERMINED AMOUNT OF INERT GAS THROUGH SAIDTUBULATION WHILE THE AFORESAID PORTION OF SAID ENVELOPE IS STILL IN ITSCOOLED CONDITION AND THE VOLATILE MATERIAL IS CONDENSED THEREON, ANDTHEN SEALING-OF THE TUBULATION AT A POINT ADJACENT SAID ENVELOPE.